Marker Band Sorter

The fully assembled Marker Band Sorter

The Marker Band Sorter, which was a collaborative senior design project from San Diego State University that began in January 2020 until December 2020. I worked in a team with 3 other mechanical engineering students, where I was the Software Lead.

My contributions to this project include:

  • Collaborated with sponsors from Johnson Matthey company and facilitated communication with project team members
  • Modified pre-existing CAD models in SolidWorks to implement them with our SolidWorks assembly
  • Analyzed stresses for each critical part and subsystem for our project
  • Developed C/C++ code for serial communication between servo motors, stepper motor drivers, stepper motors, an Arduino, and a machine vision camera
  • Designed and integrated the electrical circuitry of the Marker Band Sorter
  • Develop system level diagram of Marker Band Sorter

Check out the project website for more info!

Problem Statement:

The manufacturer, Johnson Matthey, is currently doing quality control of marker bands (small radiopaque metal bands) via manual inspection under a microscope. This process is tedious and time consuming, thus a streamlined and automated sorting method is desired.

Project Requirements:

This system must be able to sort out colored marker bands from large batches of approximately 5,000+ pieces. It must be able to sort bands that fall below the following dimensions:

  • Outer Diameter Range: 0.070” – 0.170”
  • Wall Thickness Range: 0.0018” – 0.003”
  • Length Range: 0.020” – 0.125”

The system must also be able to pause for 600ms under the camera.

Project Criteria: 

  • Machine must be tabletop size
  • Sort oversized marker bands if possible
  • Must be made out of medical grade material
  • Clearances in the machine must be large or small enough so marker bands do not get caught
  • Modular to sort a given batch of marker band sizes
  • The system must sort 125,000 parts per day. This is equivalent to approximately 1.44 marker bands per second.

Our Solution: 

An automated, machine vision sorter that sorts marker bands based on color, utilizing a Pixy2 Camera. This sorter is designed to be interchangeable with a Keyence XT-24 3D scanning camera, capable of measuring band length tolerance. In addition, this sorter will allow a bulk amount of marker bands to be automatically sorted into separate containers.

System level diagram of the Marker Band Sorter
Final CAD assembly and expanded view of assembly

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